Unit 4 Astronomy: the science of the stars
How life began on earth
教学设计
教学目标：
With the teacher’s instructions and guidance, students are expected to:
Find the main idea; explain how the life began on the earth; use
related expressions;
2. Try skimming and scanning skills; list ideas and major details;
3. Cooperate with each other; adjust reading methods according to tasks; use previous knowledge
4. Appreciate the style of the passage; be eager to explore and express
5. Learn more about the knowledge of the astronomy
教学设计：
I. Warming-up
1. In our solar system eight planets circle around the sun. What are they? Please name them in order.
2. But there used to be nine planets in the solar system. Recently scientists have decided that one of them can no longer be considered a planet. Do you know the name of that planet? Do you know why they removed it?
(Since there are eight planets in the solar system, why does life exist only on the earth instead of other planets? And how did life begin on the earth?)
II. Leading-in
About this question, in ancient times, there are some famous tales in eastern or western countries. Do you know some stories about the origin of the life on the earth?
(For example, in China, it is said that the world was created by PanGu and human beings were created by NvWa. While in western countries, people believe that the world and the human beings were created by the God.)
III. Pre-reading
But what is the scientific idea about the origin of the life?
Watch the video and try to find out how the universe began.
IV. Reading
Fast-reading.
In this text, there are five paragraphs, according to Ex1, we know that
the text can be divided into 3 parts. Please read the text quickly, and try to grasp the main idea of each paragraph.
detailed-reading
From the structure, we have a general idea of the beginning of the earth and the life. But what are details in the life development? Read the text again, finish Ex2.
Third reading
Analyze the text according to the paragraph and answer the Ex3.
(1) So from this timeline, we can know that there is a long way for the life to develop, but why did the life exist on the earth? Was the earth different from other planets? Let’s come into P2 and P3 again. And find out the answer to Q1 in Ex3 and try to describe how the earth formed.
(2) And according to ex2, we know that the plants grow before the animals, but why? Ok, read P4.Then answer Q2Q3 in Ex3 and review the development of the life.
(3) So after the man disappeared, what did they do on the earth and what problems did they cause? Read P5 and answer Q6.
V. After-reading
So from P5, we know that human beings aren’t looking after the earth well so that the earth may become too hot to live on. How to deal with it? For as students, what little things can we do for our earth in daily life?
评测练习
Unit 4 Astronomy: the science of the stars
How life began on the earth
I. Summary
After the “big bang”, the earth was still just a cloud of _______, it _______loudly with fire and rock, which were _______ to produce the_________, water vapor and other gases. Then ________ began to appear on the earth. _____________ in water are considered to be the earliest lives on the earth. The O2 they supplied encouraged the lives of________________. Slowly green plants grew on land, which were followed by __________ like insects & __________. When the plants grew into________, ______ appeared. Then _______ developed but disappeared later, which made possible the rise of a totally different animal, _______, and finally _______ spread all over the world.
II．完成句子
1. _________________________（它将会变成什么样） was a mystery until the dust began to slowly combine into a ball __________________（环绕太阳运转球体）.
2. The problem was that the earth became violent because ____________________________________________________（不知道这个固体形状是否会继续持续下去）.
3. _________________________（当地球冷却下来）, water began to appear on its surface.
4. It allowed the earth to _____________________, which had become part of the earth’s atmosphere, ______________________（把有害的气体溶解到大洋和海中）.
5. Scientists believe that _____________________________（从大气中吸取二氧化碳） and ______________________（在空气中注入氧气） helped the life to develop.
6. They are putting too much carbon dioxide into the atmosphere, which _______________________________________________（使得热量不能从地球上散发到太空中去）.
课件23张PPT。人教版必修三第四单元
Astronomy: the science of the stars
How Life Began On The EarthUnit 4
Astronomy:
the science of the starsThe Solar system eight planets
many comets
other objects 水星Comet金星地球火星木星土星天王星海王星Each religion or culture has its own ideas
about the beginning of the universe.In Chinese legend, it says ____________
created the world. He seperates the sky
from the earth and his whole _____ turns
into all kinds of things in the universe.Pangu（盘古）bodyAnother tale is that
the man is created
by __________,
who is the goddess
with the man's
_________ and the
_________ body.Nvwa（女娲）headsnake'sthe GodAdam and EveIn Bible,the world and the whole universe
was created by __________, who created
the first man and the first woman called
________________.How Life Began on the EarthThe universe began with a “Big Bang ” A widely accepted theory
about the beginning of the _________ The formation of the ____ The importance of _____
for life The development of _____
and ________ on the earth The arrival of _______and their activities’ ______ on the earthwaterearthuniverseplantshumanseffectRead the text quickly and write down the main idea for each paragraph.animals（ ）Insects and amphibians appeared.
（ ）Dinosaurs appeared.
（ ）The earth became a solid ball.
（ ）Small plants grew on the water.
（ ）Reptiles appeared.
（ ）Plants began to grow on dry land.
（ ）The earth was a cloud of dust.
（ ）Water appeared on the earth.
（ ）Shellfish and other fish appeared.
（ ）The universe began with a “Big Bang”.
（ ）Clever animals with hands and feet appeared.
（ ）Mammals appeared.51062948371 Careful readingPut the order of development of life into a time line. 12 11 Detailed readingTask 1: Read the paragraph 2 & 3.
Answer the question 1 of Ex3 on P27 and try to
describe how the earth formed.
1. Why was the earth different from the other
planets?
Because water remained on the earth.
A cloud of dust
Combine into a solid ball
Explode…with fire & rock
(produce H2O, CO2,O2, N2, other gases) atmosphereCool downwater appeared dissolve harmful gases into … Life developedTask 2: Read the paragraph 4.
Answer the question 2&3 of Ex3 on P27 and try to
describe how the life developed.
2. Why did the plants grow before the animals came?
Because plants provided oxygen for animals to breathe.
3. Why is it wrong to show films with dinosaurs and
people together?
Because dinosaurs died out long before human beings
developed on the earth.Detailed readingThe development of lifeA cloud of dust → a solid ball →
presence of water
small plant grows on the water
shellfish and other fish appear
plants begin to grow on dry land
insects and amphibians appear
reptiles appear
dinosaurs appear
mammals appearHumans appear They developed new methods of growing food, hunting and moving around. As time went by they covered the earth and have become the most important animals on the planet.Greenhouse effectBut they are not taking care of the earth very well. They are putting too much carbon dioxide into the atmosphere, which prevents heat from escaping from the earth into space.What problems?Too hotThe earth may become too hot for them to lives on. futureWhether life will continue on the earth for million years to come will depend on whether this problem can be solved.After the “big bang”, the earth was still just a cloud of
_______, it _______loudly with fire and rock, which were
_______ to produce the_________, water vapour and other
gases. Then ________ began to appeared on the earth.
______________ in water are considered to be the earliest
lives on the earth. The O2 they supplied encouraged the
lives of________________. Slowly green plants grew on
land, which were followed by __________ like insects &
__________. When the plants grew into________, ______
appeared. Then _______ developed but disappeared later,
which made the rise of a totally different animal,_______,
possible, and finally _______ spread all over the world.dustexplodedin timeco 2watersummarySmall plantsshell-fish and fishland animalsamphibiansforestsreptilesdinosaursmammalhumansAfter-readingSo for us students, what little things can we do for the earth in our daily life?Save water and electricity
Walk or ride a bike to the school
Recycle the paper
Change the light bulbs
Sort out rubbishTaking good care of the earth is taking good care of ourselves!Homework
Go over the text and retell the evolution of life on the earth.
